Search the "extra libs" in GUIX_KF5INIT_LIB_PATH (which basically is a
collection of all /lib directories). We can not hard-code the full path to the
libsKF5Plasam, since adding palse-workspace

Adopted from NixOS
pkgs/development/libraries/kde-frameworks/kinit/kdeinit-extra_libs.patch

===================================================================
--- kinit-5.32.0/src/kdeinit/kinit-5.32.0/src/kdeinit/.orig
+++ kinit-5.32.0/src/kdeinit/kinit.cpp
@@ -96,11 +96,9 @@
     "libKF5Parts.5.dylib",
     "libKF5Plasma.5.dylib"
 #else
-    "libKF5KIOCore.so.5",
-    "libKF5Parts.so.5",
-//#ifdef __KDE_HAVE_GCC_VISIBILITY // Removed for KF5, we'll see.
-    "libKF5Plasma.so.5"
-//#endif
+    "GUIX_PKGS_KF5_KIO/lib/libKF5KIOCore.so.5",
+    "GUIX_PKGS_KF5_PARTS/lib/libKF5Parts.so.5",
+    "GUIX_PKGS_KF5_PLASMA/lib/libKF5Plasma.so.5"
 #endif
 };
 #endif
@@ -1533,20 +1531,6 @@ static int initXconnection()
 }
 #endif
 
-#ifndef Q_OS_OSX
-// Find a shared lib in the lib dir, e.g. libkio.so.
-// Completely unrelated to plugins.
-static QString findSharedLib(const QString &lib)
-{
-    QString path = QFile::decodeName(CMAKE_INSTALL_PREFIX "/" LIB_INSTALL_DIR "/") + lib;
-    if (QFile::exists(path)) {
-        return path;
-    }
-    // We could also look in LD_LIBRARY_PATH, but really, who installs the main libs in different prefixes?
-    return QString();
-}
-#endif
-
 extern "C" {
 
     static void secondary_child_handler(int)
@@ -1689,7 +1693,7 @@
     if (!d.suicide && qEnvironmentVariableIsEmpty("KDE_IS_PRELINKED")) {
         const int extrasCount = sizeof(extra_libs) / sizeof(extra_libs[0]);
         for (int i = 0; i < extrasCount; i++) {
-            const QString extra = findSharedLib(QString::fromLatin1(extra_libs[i]));
+            const QString extra = QString::fromLatin1(extra_libs[i]);
             if (!extra.isEmpty()) {
                 QLibrary l(extra);
                 l.setLoadHints(QLibrary::ExportExternalSymbolsHint);
74669fea29adef6aa949cc'>root</a>/<a href='/guix/log/ROADMAP?id=a057d2acbf8d78afe474669fea29adef6aa949cc'>ROADMAP</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/ROADMAP?id=a057d2acbf8d78afe474669fea29adef6aa949cc&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-05-20 01:58:04 +0200'>2021-05-20</span></td><td><a href='/guix/commit/ROADMAP?id=c0087d33705f53cc3619a1a43a33602aaecc3a8b'>The #guix channel is hosted by Libera Chat.</a><span class='msg-avail'>...<span class='msg-tooltip'>* README (Contact): Update network name.
* ROADMAP: Likewise.
* doc/contributing.texi (Contributing): Likewise.
* doc/guix.texi (After System Installation): Likewise.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2016-01-29 20:21:54 +0300'>2016-01-29</span></td><td><a href='/guix/commit/ROADMAP?id=171a0a13a4350ac9bbed0f2ed8e9c9777cc57b22'>Rename 'dmd' to 'shepherd' in comments and strings.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/hydra/demo-os.scm (operating-system)[issue]: Point to
  shepherd instead of dmd.
* ROADMAP: Likewise.
* gnu/build/install.scm (directives): Adjust comment.
</span></span></td><td>Alex Kost</td></tr>
<tr><td><span title='2015-01-22 22:52:11 +0100'>2015-01-22</span></td><td><a href='/guix/commit/ROADMAP?id=5bf6b86f1b5b12a55305b0dc8030a6f8f2005f01'>doc: Update 'ROADMAP'.</a><span class='msg-avail'>...<span class='msg-tooltip'>Suggested by Omar Radwan &lt;toxemicsquire4@gmail.com&gt;.

* ROADMAP: Rewrite.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2014-01-03 18:19:58 +0100'>2014-01-03</span></td><td><a href='/guix/commit/ROADMAP?id=48ad99db25cf8a60b5d0d3dc333aee89ce8aba8f'>doc: Update 'ROADMAP'.</a><span class='msg-avail'>...<span class='msg-tooltip'>* ROADMAP: Add link to the updated road map, and the a note on release
  history.
</span></span></td><td>Ludovic Courtès</td></tr>